PET/CT May Improve Imaging of Recurrent Prostate Cancer

Early study results are encouraging, but high-quality data that validate PET/CT against a reliable reference standard are lacking.

Positron emission tomography (PET)-based imaging may offer a promising alternative to conventional imaging for characterizing the true extent of disease in men who experience early biochemical recurrence following primary treatment for prostate cancer (PCa), according to a new systematic review and meta-analysis published in the World Journal of Urology.

Niranjan J. Sathianathen, MBBS, of the University of Minnesota in Minneapolis, and colleagues identified 21 studies including 3202 patients who underwent PET/computed tomography (CT) using the radiolabeled tracers 11C-choline, 18F-FACBC, or 68Ga-PSMA. The sensitivities of these tracers were 80.9%, 79.7%, and 76.4%, respectively. The specificities were 84.1%, 61.9%, and 99.8%.

Detection rates ranged between 58.6 and 82.8%, with a median PSA less than 5 ng/mL in most studies.

Conventional imaging modalities such as CT, bone scintigraphy, and magnetic resonance imaging commonly fail to detect low-volume locally recurrent or metastatic disease, especially at low PSA levels, according to the researchers. “The early results are encouraging that these techniques are superior to conventional imaging modalities, which would allow salvage therapies to be optimized,” Dr Sathianathen and the team concluded.

The authors pointed out, however, there is a lack of high-quality studies that validate the findings from PET/CT against a reliable reference standard, “and therefore, it is challenging to accurately characterize the diagnostic performance of these tests.”

The investigators acknowledged that the studies had a high risk for bias. Although PET/CT results were corroborated by pathology, further imaging, or clinical response, the optimal tool for validation has yet to be determined.